Conventionally in such apparatus, an imaging distance of an X-ray tube (an X-ray irradiating device) to a subject is fixed. An X-ray detector (an X-ray detecting device) is then moved for every exposure in consideration of overlap of an exposure area from the X-ray tube in every sheet and a position of the X-ray detector within a long-length imaging area. See, for example, Japanese Patent Publications No. JP-A-2004-358254, JP-A-2007-135692, and JP-A-2007-185209.
In this case, examples of an imaging method includes a method of moving a focusing position of the X-ray tube parallel to the X-ray detector for every exposure as described in the prior art of JP-A-2007-135692 and in JP-A-2007-185209. Moreover, the examples include a method of varying an exposure angle of the X-ray tube for every exposure such that X-rays enter into the X-ray detector with a focusing position of the X-ray tube being fixed as described in JP-A-2004-358254 and JP-A-2007-135692. Subsequently, two or more successive X-ray images obtained for every exposure are combined in a direction of movement, whereby an X-ray image with a long area (long X-ray image) can be obtained.
Such approach as shown in FIG. 12 is conducted for determination of the long-length imaging area. As shown in FIG. 12, an X-ray tube 102 with a line marker 101 attached thereto as an illumination device is moved into a given position to determine an imaging distance D between the X-ray tube 102 and a subject M. Subsequently, the X-ray tube 102 is inclined with a focus of the X-ray tube 102 being fixed at the position, whereby the line marker 101 is also inclined. The X-ray tube 102 is inclined and an upper edge or a lower edge of the imaging area is illuminated by the line marker 101. Thereafter, a positioning button (e.g., a button on a touch panel attached to the X-ray tube 102) is depressed, whereby each position corresponding to the upper and lower edges is determined. The imaging area L can be determined geometrically from the determined imaging distance D and angles α, β of the X-ray tube 102 upon illuminating the upper and lower edges. In order to obtain a practical X-ray image, an X-ray detector 103 is moved such that X-rays enter into the X-ray detector 103.
Upon conducting radiography for obtaining a practical X-ray image, the imaging distance D and the imaging area L are determined. Then the X-ray tube 102 is inclined by an operator through depressing the exposure button by an operator, and the X-ray detector 103 is moved into a first exposure position such that X-rays emitted from the inclined X-ray tube 102 enter. Thereby radiography can be conducted. When radiography of a first X-ray image obtained in the first exposure position is completed, the X-ray tube 102 is inclined and the X-ray detector 103 is moved into a second exposure position. Likewise, radiography for obtaining X-ray images is repeated through inclination of the X-ray tube 102 and movement of the X-ray detector 103 until the number of images can be obtained with which the long-length imaging area can be covered. Here, the adjacent X-ray images overlap partially when combining them.
The movable area of the X-ray tube 102 or the X-ray detector 103 is restricted mechanically. For instance, when X-ray radiography is conducted while the subject is in a standing posture, the X-ray detector 103 is held on an erect stand while the movable area thereof is restricted through strut stroke of the erect stand. Consequently, the long-length imaging area is also restricted. Thus in order to obtain an area for the long imaging area where radiography is possible in determining the imaging area for the long-length imaging mentioned previously, notification is provided to the operator by changing display of the foregoing positioning button, for example, when the position of the upper edge or the lower edge is determined. Specifically, notification is provided to the operator by changing a color of the button into a background color of the foregoing touch pane to be undisplayed or by changing a shape of the button.
The conventional apparatus with such construction has the following drawback. Specifically, the upper edge and the lower edge of the long-length imaging area can be determined with the simple operation mentioned previously. On the other hand, upon determination of the upper and lower edges, operation should be performed while paying simultaneous attention to light from the illumination device toward the subject and the shape of the foregoing positioning button. Consequently, actual operation becomes extremely complicated. Such drawback may arise.
This invention has been made regarding the state of the art noted above, and its object is to provide an X-ray apparatus that can facilitate operation upon determination of an imaging area.